在 JFrame 上更改 JPanel 组件时无法显示它
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【中文标题】在 JFrame 上更改 JPanel 组件时无法显示它【英文标题】：I can't display my JPanel components when I change it on a JFrame 【发布时间】：2012-03-11 03:14:04 【问题描述】：我似乎无法在框架上显示我的面板组件。有人可以帮忙吗？ 我只是给了我一个空白的 JFrame。上面没有更多组件。
import javax.swing.JPanel;
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/*
* Main.java
*
* Created on 20 Feb 2012, 6:51:55 PM
*/
/**
*
* @author User
*/
public class Main extends javax.swing.JFrame
NewGameSettings ng = new NewGameSettings();
/** Creates new form Main */
public Main()
initComponents();
/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents()
newgame = new javax.swing.JButton();
loadgame = new javax.swing.JButton();
exit = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle("Java game");
setResizable(false);
newgame.setFont(new java.awt.Font("Arial", 0, 18));
newgame.setForeground(new java.awt.Color(0, 0, 255));
newgame.setText("New Game");
newgame.setBorder(null);
newgame.setBorderPainted(false);
newgame.setContentAreaFilled(false);
newgame.setCursor(new java.awt.Cursor(java.awt.Cursor.HAND_CURSOR));
newgame.addActionListener(new java.awt.event.ActionListener()
public void actionPerformed(java.awt.event.ActionEvent evt)
newgameActionPerformed(evt);
);
loadgame.setFont(new java.awt.Font("Arial", 0, 18));
loadgame.setForeground(new java.awt.Color(0, 0, 255));
loadgame.setText("Load Game");
loadgame.setBorder(null);
loadgame.setBorderPainted(false);
loadgame.setContentAreaFilled(false);
loadgame.setCursor(new java.awt.Cursor(java.awt.Cursor.HAND_CURSOR));
loadgame.addActionListener(new java.awt.event.ActionListener()
public void actionPerformed(java.awt.event.ActionEvent evt)
loadgameActionPerformed(evt);
);
exit.setFont(new java.awt.Font("Arial", 0, 18));
exit.setForeground(new java.awt.Color(0, 0, 255));
exit.setText("Exit");
exit.setBorder(null);
exit.setBorderPainted(false);
exit.setContentAreaFilled(false);
exit.setCursor(new java.awt.Cursor(java.awt.Cursor.HAND_CURSOR));
exit.addActionListener(new java.awt.event.ActionListener()
public void actionPerformed(java.awt.event.ActionEvent evt)
exitActionPerformed(evt);
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(527, 527, 527)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(loadgame)
.addComponent(newgame)))
.addGroup(layout.createSequentialGroup()
.addGap(570, 570, 570)
.addComponent(exit)))
.addContainerGap(580, Short.MAX_VALUE))
);
layout.linkSize(javax.swing.SwingConstants.HORIZONTAL, new java.awt.Component[] loadgame, newgame);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(157, 157, 157)
.addComponent(newgame)
.addGap(164, 164, 164)
.addComponent(loadgame)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 252, Short.MAX_VALUE)
.addComponent(exit)
.addGap(108, 108, 108))
);
layout.linkSize(javax.swing.SwingConstants.VERTICAL, new java.awt.Component[] loadgame, newgame);
pack();
// </editor-fold>
private void newgameActionPerformed(java.awt.event.ActionEvent evt)
// TODO add your handling code here:
this.getContentPane().removeAll();
this.getContentPane().add(ng);
this.invalidate(); //I dont know how it isnt working
private void loadgameActionPerformed(java.awt.event.ActionEvent evt)
// TODO add your handling code here:
private void exitActionPerformed(java.awt.event.ActionEvent evt)
// TODO add your handling code here:
System.exit(0);
/**
* @param args the command line arguments
*/
public static void main(String args[])
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels())
if ("Nimbus".equals(info.getName()))
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
catch (ClassNotFoundException ex)
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
catch (InstantiationException ex)
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
catch (IllegalAccessException ex)
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
catch (javax.swing.UnsupportedLookAndFeelException ex)
java.util.logging.Logger.getLogger(Main.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable()
public void run()
new Main().setVisible(true);
);
// Variables declaration - do not modify
private javax.swing.JButton exit;
private javax.swing.JButton loadgame;
private javax.swing.JButton newgame;
// End of variables declaration
面板…………
import javax.swing.JOptionPane;
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/*
* NewGameSettings.java
*
* Created on 20 Feb 2012, 8:32:08 PM
*/
/**
*
* @author User
*/
public class NewGameSettings extends javax.swing.JPanel
/** Creates new form NewGameSettings */
public NewGameSettings()
initComponents();
/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents()
buttonGroup1 = new javax.swing.ButtonGroup();
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();//a
username = new javax.swing.JTextField();//b
password = new javax.swing.JPasswordField();//k
eco = new javax.swing.JRadioButton();
engi = new javax.swing.JRadioButton();
gen = new javax.swing.JRadioButton();
jButton1 = new javax.swing.JButton();
jLabel1.setText("Username");
jLabel2.setText("Password");
buttonGroup1.add(eco);
eco.setText("Economist");
eco.addActionListener(new java.awt.event.ActionListener()
public void actionPerformed(java.awt.event.ActionEvent evt)
ecoActionPerformed(evt);
);
buttonGroup1.add(engi);
engi.setText("Engineer");
engi.addActionListener(new java.awt.event.ActionListener()
public void actionPerformed(java.awt.event.ActionEvent evt)
engiActionPerformed(evt);
);
buttonGroup1.add(gen);
gen.setText("General");
jButton1.setFont(new java.awt.Font("Arial", 0, 14)); // NOI18N
jButton1.setForeground(new java.awt.Color(0, 0, 255));
jButton1.setText("ready");
jButton1.setBorderPainted(false);
jButton1.setContentAreaFilled(false);
jButton1.setCursor(new java.awt.Cursor(java.awt.Cursor.HAND_CURSOR));
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
this.setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(314, 314, 314)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel2)
.addComponent(jLabel1))
.addGap(145, 145, 145)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addGroup(layout.createSequentialGroup()
.addComponent(eco)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(engi)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(gen))
.addComponent(username, javax.swing.GroupLayout.DEFAULT_SIZE, 259, Short.MAX_VALUE)
.addComponent(password)))
.addGroup(layout.createSequentialGroup()
.addGap(1037, 1037, 1037)
.addComponent(jButton1)))
.addContainerGap(94, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(107, 107, 107)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel1)
.addComponent(username, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(31, 31, 31)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(password, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(99, 99, 99)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(eco)
.addComponent(engi)
.addComponent(gen))
.addGap(380, 380, 380)
.addComponent(jButton1)
.addContainerGap(45, Short.MAX_VALUE))
);
// </editor-fold>
private void ecoActionPerformed(java.awt.event.ActionEvent evt)
// TODO add your handling code here:
JOptionPane.showMessageDialog(null,"With the economist class you get 25% intrest income on money in the bank ","Economist advantages ",JOptionPane.INFORMATION_MESSAGE);
private void engiActionPerformed(java.awt.event.ActionEvent evt)
// TODO add your handling code here:
// Variables declaration - do not modify
private javax.swing.ButtonGroup buttonGroup1;
private javax.swing.JRadioButton eco;
private javax.swing.JRadioButton engi;
private javax.swing.JRadioButton gen;
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JPasswordField password;
private javax.swing.JTextField username;
// End of variables declaration
谁能帮我解决这个问题？请
【问题讨论】：
【参考方案1】：您是否将您的 NameGameSettings 面板添加到您的父 JFrame？如果不是，这可能是问题所在。
【讨论】：
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